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The introduction of stem cells as multipotent
Russian academic Alexander Maximow lectures at the Berlin Hematological Society on a theory that all blood cells come from the same ancestor cell. This introduces the idea of blood stem cells that are multi-potent, or have the ability to differentiate into several types of cells, in the process first introducing this idea of all stem cells. -
The physical discovery of pluripotent stem cells
Leroy Stevens, while dissecting a mouse, discovers a tumor called a teratoma in its scrotum, which contains a strange mass of both differentiated and undifferentiated cells. -
First successful bone marrow transplant between identical twins
Dr. E. Donnall Thomas operates this transplant, and later reports that total body irradiation followed by infusion of marrow from an identical twin could result in complete remission of leukemia. -
First indications of blood stem cells
Canadian scientists Ernest McCulloch and James Till perform experiments on the bone marrow of mice and observe that different blood cells come from a special class of cells. This is one of the first pieces of evidence of blood stem cells. -
First successful bone marrow transplant between non-identical siblings
Robert A. Good of the University of Minnesota performs the first successful bone marrow transplant on a child patient suffering from an immune deficiency that killed others in his family. The boy received bone marrow from his sister, and he grew into healthy adulthood. -
Leroy Stevens makes a game changing discovery
Further research into teratomas leads Stevens to discover that the the cells that begin the growth of the teratoma are pluripotent embryonic stem cells. This confirms Alexander Maximow's theory. -
Congress fights embryonic stem cell research
The 93rd Congress implements a ban on nearly all federally funded fetal tissue research until the National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research devises guidelines for it. -
First isolation of embryonic stem cells
Two scientists, Martin Evans of the University of Cambridge and Gail Martin of the University of California, San Francisco, conduct separate studies and derive pluripotent stem cells from the embryos of mice, the first embryonic stem cells ever to be isolated. -
The first successful adult cell regeneration
Andrew Lassar and Harold Weintraub of Seattle, Washington, report results from an experiment in which they converted rodent fibroblasts (a type of connective tissue) directly into myoblasts (which generate muscle cells), using a single gene (MyoD). Being able to convert one type of adult cell into another may be important for regenerative medicine. -
Introducing the "knockout" mice
Researchers Mario Capecchi, Martin Evans and Oliver Smithies come together to creat the first "knockout" mice from a combination of embryonic stem cells and homologous recombination, a process in which similar strands of DNA switch genes. These mice were bred to be missing certain genetic sequences. Since the first patients, over 500 mouse analogs of human disease have been made. -
Evidence of cancer stem cells
Dominique Bonnet and John Dick of Canada discover that leukemia comes from the same stem cells that make our blood cells. This is one of the first major studies to say that cancer grows out of stem cells gone off course, supporting the concept of “cancer stem cells." -
Isolating the first human embryonic stem cells
A team at the University of Wisconsin, Madison, led by James Thomson and Jeffrey Jones, reports the creation of the first batch of human embryonic stem cells, which they derived from early embryos. After finding the cells were pluripotent, the team sees the potential the cells have for drug discovery and transplantation medicine -
Creating sperm cells from stem cells
George Q. Daley and his team publish findings on converting stem cells from mice into germ cells and, eventually, primitive sperm cells that are able to fertilize egg cells. These embryonic germ cells give scientists a chance to study different processes, including cancer growth and the development of sperm cells -
First female stem cell organ transplant
Claudia Castillo becomes the first woman to have an organ grown from her own stem cells transplanted into herself. In this case, it is her windpipe. -
FDA finally approves embryonic stem cell based therapy
Geron Corporation announces the FDA’s approval for a limited phase I trial of Geron’s new treatment for spinal cord injuries. This was the first FDA approval of a clinical trial for a therapy based on human embryonic stem cells.